MJ's Ex-HousekeeperKey Witness in Wade'sMolestation Lawsuit

5/18/2013 12:45 PM PDT

The Neverland housekeeper who graphically described seeing Wade Robson naked in a shower with Michael Jackson ... will play a huge role in whether Robson wins a cent from MJ's Estate in his new civil lawsuit, TMZ has learned.

Sources close to the case tell us Wade's lawyers are dissecting Blanca Francia's testimony during Jackson's 2005 molestation trial.

During the trial, Francia -- who worked at Neverland in the late '80s -- testified she witnessed Jackson showering naked with a 7 or 8-year-old Wade.

We obtained a transcript of the testimony in which Francia describes seeing Michael's underwear on the floor outside the shower, as well as Wade's child-sized neon green underwear.

She said she couldn't see what Michael was doing exactly because the shower door was fogged up, but said she heard him laughing.

Ultimately, Francia's testimony wasn't enough to sway the jury -- MJ was acquitted -- partly because Wade himself also testified, but insisted Michael never touched him.

TMZ broke the story ... Wade is planning to argue that MJ's companies -- MJJ Productions and MJJ Ventures -- had a duty to protect him because they were involved in recruiting him from Australia to work with Michael.

According to sources, Wade wants to use Blanca's testimony to show Michael abused him as a child. We're told Wade's lawyers are also trying to contact her to see if she will cooperate in the new case.